Question 1

A Josephson junction consists of

Accepted Answer

A)  two superconductors separated by a thin insulating barrier. 
B)  a superconductor sandwiched between two insulating barriers. 
C)  two different superconductors in contact with each other. 
D)  a superconductor in contact with a conductor warmer than 4.2 K. 
E)  None of these is correct. 
A)  two superconductors separated by a thin insulating barrier. 
B)  a superconductor sandwiched between two insulating barriers. 
C)  two different superconductors in contact with each other. 
D)  a superconductor in contact with a conductor warmer than 4.2 K. 
E)  None of these is correct.

Question 2

The average energy of a Fermi electron gas at T = 0 is

Accepted Answer

A)  3kT/2 
B)  EF  
C)  kT 
D)  zero 
E)  3EF/5 
A)  3kT/2 
B)  EF  
C)  kT 
D)  zero 
E)  3EF/5

Question 3

The probability that an energy state in copper 0.2 eV above the Fermi energy is occupied at T = 300 K is

Accepted Answer

A)  0.0365% 
B)  0.0404% 
C)  0.0438% 
D)  0.0457% 
E)  0.0496% 
A)  0.0365% 
B)  0.0404% 
C)  0.0438% 
D)  0.0457% 
E)  0.0496%

Question 4

If you apply a voltage of 0.3 µV to a Josephson junction, you can expect to measure a frequency of approximately

Accepted Answer

A)  327 MHz 
B)  484 Hz 
C)  145 kHz 
D)  484 MHz 
E)  145 MHz 
A)  327 MHz 
B)  484 Hz 
C)  145 kHz 
D)  484 MHz 
E)  145 MHz

Question 5

The graph that correctly shows the dependence of resistance on temperature for mercury is

Accepted Answer

A)  1 
B)  2 
C)  3 
D)  4 
E)  5 
A)  1 
B)  2 
C)  3 
D)  4 
E)  5

Question 6

The probability that an energy state in copper 0.05 eV above the Fermi energy is occupied at T = 300 K is

Accepted Answer

A)  1.26% 
B)  2.52% 
C)  3.78% 
D)  12.6% 
E)  14.5% 
A)  1.26% 
B)  2.52% 
C)  3.78% 
D)  12.6% 
E)  14.5%

Question 7

Insulators are poor conductors of electricity because

Accepted Answer

A)  there is a small energy gap between the valence band and the next higher band in which electrons can collect. 
B)  there is a large energy gap between the valence band and the next higher band in which electrons can collect. 
C)  the valence band has a few vacancies for electrons. 
D)  the valence band is only partly full. 
E)  None of these is correct. 
A)  there is a small energy gap between the valence band and the next higher band in which electrons can collect. 
B)  there is a large energy gap between the valence band and the next higher band in which electrons can collect. 
C)  the valence band has a few vacancies for electrons. 
D)  the valence band is only partly full. 
E)  None of these is correct.

Question 8

According to the BCS theory,

Accepted Answer

A)  electrons in a superconductor are coupled in pairs at low temperatures. 
B)  electrons in a Cooper pair have equal and opposite spins. 
C)  electrons in a Cooper pair act as a single particle with zero spin. 
D)  any number of Cooper pairs may be in the same quantum state with the same energy. 
E)  All of these are true. 
A)  electrons in a superconductor are coupled in pairs at low temperatures. 
B)  electrons in a Cooper pair have equal and opposite spins. 
C)  electrons in a Cooper pair act as a single particle with zero spin. 
D)  any number of Cooper pairs may be in the same quantum state with the same energy. 
E)  All of these are true.

Question 9

The probability that an energy state in magnesium 0.05 eV above the Fermi energy is occupied at T = 300 K is

Accepted Answer

A)  1.26% 
B)  2.52% 
C)  3.78% 
D)  12.6% 
E)  14.5% 
A)  1.26% 
B)  2.52% 
C)  3.78% 
D)  12.6% 
E)  14.5%

Question 10

The resistivity of iron at 20ºC is 10 *10-8 $\sigma$ · m and the number of electrons per cubic centimeter is 17.0 *1022. If you take the average speed of the electrons to be equal to their root-mean-square speed (at T = 300 K) of 1.17 *105 m/s, it follows that their mean free path, $\lambda$, must be

Accepted Answer

A)  0.245 nm 
B)  0.317 nm 
C)  0.428 nm 
D)  0.556 nm 
E)  None of these is correct. 
A)  0.245 nm 
B)  0.317 nm 
C)  0.428 nm 
D)  0.556 nm 
E)  None of these is correct.

Question 11

The resistivity of copper at 20ºC is 1.7* 10-8  $\Omega$· m. You have copper wire whose diameter is 2.00 mm and need a resistance of 1.00  $\Omega$. How long would a piece of this wire need to be to provide this resistance?

Accepted Answer

A)  19.6 m 
B)  49.1 m 
C)  185 m 
D)  317 m 
E)  542 m 
A)  19.6 m 
B)  49.1 m 
C)  185 m 
D)  317 m 
E)  542 m

Question 12

An 8-gauge copper wire (diameter = 3.665 mm) carries a current of 40 A. The current density of the wire is

Accepted Answer

A)  1.52 * 107 A/m2 
B)  3.79 * 106 A/m2 
C)  1.90 * 106 A/m2 
D)  1.21 * 106 A/m2 
E)  None of these is correct. 
A)  1.52 * 107 A/m2 
B)  3.79 * 106 A/m2 
C)  1.90 * 106 A/m2 
D)  1.21 * 106 A/m2 
E)  None of these is correct.

Question 13

A semiconductor for which it is true that the major charge carriers are holes

Accepted Answer

A)  is called an n-type semiconductor. 
B)  is called a p-type semiconductor. 
C)  accepts positive charges from filled valence bands. 
D)  is devoid of acceptor levels. 
E)  None of these is correct. 
A)  is called an n-type semiconductor. 
B)  is called a p-type semiconductor. 
C)  accepts positive charges from filled valence bands. 
D)  is devoid of acceptor levels. 
E)  None of these is correct.

Question 14

Using the measured mass density of 2.48 g/cm3, and the molar mass of 58.098 g for KF, the equilibrium spacing between the K+ and F- ions is

Accepted Answer

A)  0.168 nm 
B)  0.196 nm 
C)  0.269 nm 
D)  0.293 nm 
E)  0.312 nm  
A)  0.168 nm 
B)  0.196 nm 
C)  0.269 nm 
D)  0.293 nm 
E)  0.312 nm

Question 15

The crystalline structure known as body-centered-cubic

Accepted Answer

A)  is characterized by the stacking of identical spheres. 
B)  occurs when each ion has eight nearest-neighbor ions of opposite charge. 
C)  corresponds to an alternating pattern of ions. 
D)  occurs when an ion of either kind has six nearest neighbors of the other kind. 
E)  None of these is correct. 
A)  is characterized by the stacking of identical spheres. 
B)  occurs when each ion has eight nearest-neighbor ions of opposite charge. 
C)  corresponds to an alternating pattern of ions. 
D)  occurs when an ion of either kind has six nearest neighbors of the other kind. 
E)  None of these is correct.

Question 16

Which of the following expressions correctly describes the dependence of the resistivity $\rho$ on the electronic mass, me,  the number of conduction electrons ne, the electronic charge e, the mean electron speed vav, and the mean free path $\lambda$?

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 17

Reverse biasing of a pn junction tends to

Accepted Answer

A)  increase the potential difference across a junction, thereby encouraging diffusion. 
B)  decrease the potential difference across a junction, thereby encouraging diffusion. 
C)  decrease the potential difference across a junction, thereby inhibiting diffusion. 
D)  increase the potential difference across a junction, thereby inhibiting diffusion. 
E)  None of these is correct. 
A)  increase the potential difference across a junction, thereby encouraging diffusion. 
B)  decrease the potential difference across a junction, thereby encouraging diffusion. 
C)  decrease the potential difference across a junction, thereby inhibiting diffusion. 
D)  increase the potential difference across a junction, thereby inhibiting diffusion. 
E)  None of these is correct.

Question 18

The crystalline structure known as hexagonal close-packed

Accepted Answer

A)  is characterized by the stacking of identical spheres. 
B)  occurs when every ion has eight nearest-neighbor ions of opposite charge. 
C)  corresponds to an alternating pattern of ions. 
D)  occurs when an ion of either kind has six nearest neighbors of the other kind. 
E)  None of these is correct. 
A)  is characterized by the stacking of identical spheres. 
B)  occurs when every ion has eight nearest-neighbor ions of opposite charge. 
C)  corresponds to an alternating pattern of ions. 
D)  occurs when an ion of either kind has six nearest neighbors of the other kind. 
E)  None of these is correct.

Question 19

Use the following to answer the next question.
 
-The speed of a conduction electron whose energy is equal to the Fermi energy EF for magnesium is

Accepted Answer

A)  1.42 * 106 m/s 
B)  1.84 *106 m/s 
C)  1.21 * 106 m/s 
D)  2.03 * 106 m/s 
E)  1.58*106 m/s 
A)  1.42 * 106 m/s 
B)  1.84 *106 m/s 
C)  1.21 * 106 m/s 
D)  2.03 * 106 m/s 
E)  1.58*106 m/s

Question 20

The frequency of the current observed at a Josephson junction is 345 MHz. The voltage applied to the junction to produce this current was

Accepted Answer

A)  1.43 µV 
B)  1.43 V 
C)  0.715 µV 
D)  0.715 mV 
E)  1.28 µV 
A)  1.43 µV 
B)  1.43 V 
C)  0.715 µV 
D)  0.715 mV 
E)  1.28 µV

A Josephson junction consists of

The average energy of a Fermi electron gas at T = 0 is

The probability that an energy state in copper 0.2 eV above the Fermi energy is occupied at T = 300 K is

If you apply a voltage of 0.3 µV to a Josephson junction, you can expect to measure a frequency of approximately

The graph that correctly shows the dependence of resistance on temperature for mercury is

The probability that an energy state in copper 0.05 eV above the Fermi energy is occupied at T = 300 K is

Insulators are poor conductors of electricity because

According to the BCS theory,

The probability that an energy state in magnesium 0.05 eV above the Fermi energy is occupied at T = 300 K is

The resistivity of copper at 20ºC is 1.7* 10^-8 $\Omega$ · m. You have copper wire whose diameter is 2.00 mm and need a resistance of 1.00 $\Omega$ . How long would a piece of this wire need to be to provide this resistance?

An 8-gauge copper wire (diameter = 3.665 mm) carries a current of 40 A. The current density of the wire is

A semiconductor for which it is true that the major charge carriers are holes

Using the measured mass density of 2.48 g/cm³, and the molar mass of 58.098 g for KF, the equilibrium spacing between the K⁺ and F^- ions is

The crystalline structure known as body-centered-cubic

Which of the following expressions correctly describes the dependence of the resistivity $\rho$ on the electronic mass, m_e, the number of conduction electrons n_e, the electronic charge e, the mean electron speed v_av, and the mean free path $\lambda$ ?

Reverse biasing of a pn junction tends to

The crystalline structure known as hexagonal close-packed

Use the following to answer the next question. -The speed of a conduction electron whose energy is equal to the Fermi energy E_F for magnesium is

The frequency of the current observed at a Josephson junction is 345 MHz. The voltage applied to the junction to produce this current was

The Electric Field I: Discrete Charge Distributions

The Electric Field II: Continuous Charge Distributions

Electric Potential

Capacitance

Electric Current and Direct-Current Circuits

The Magnetic Field

Sources of the Magnetic Field

Magnetic Induction

Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

Interference and Diffraction

Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

Atoms

Molecules

Relativity

Nuclear Physics

Elementary Particles and the Beginning of the Universe

Filters

Exam 18: Solids and the Theory of Conduction

A Josephson junction consists of

The average energy of a Fermi electron gas at T = 0 is

The probability that an energy state in copper 0.2 eV above the Fermi energy is occupied at T = 300 K is

If you apply a voltage of 0.3 µV to a Josephson junction, you can expect to measure a frequency of approximately

The graph that correctly shows the dependence of resistance on temperature for mercury is

The probability that an energy state in copper 0.05 eV above the Fermi energy is occupied at T = 300 K is

Insulators are poor conductors of electricity because

According to the BCS theory,

The probability that an energy state in magnesium 0.05 eV above the Fermi energy is occupied at T = 300 K is

The resistivity of copper at 20ºC is 1.7* 10-8 Ω\OmegaΩ · m. You have copper wire whose diameter is 2.00 mm and need a resistance of 1.00 Ω\OmegaΩ . How long would a piece of this wire need to be to provide this resistance?

An 8-gauge copper wire (diameter = 3.665 mm) carries a current of 40 A. The current density of the wire is

A semiconductor for which it is true that the major charge carriers are holes

Using the measured mass density of 2.48 g/cm3, and the molar mass of 58.098 g for KF, the equilibrium spacing between the K+ and F- ions is

The crystalline structure known as body-centered-cubic

Which of the following expressions correctly describes the dependence of the resistivity ρ\rhoρ on the electronic mass, me, the number of conduction electrons ne, the electronic charge e, the mean electron speed vav, and the mean free path λ\lambdaλ ?

Reverse biasing of a pn junction tends to

The crystalline structure known as hexagonal close-packed

Use the following to answer the next question. -The speed of a conduction electron whose energy is equal to the Fermi energy EF for magnesium is

The frequency of the current observed at a Josephson junction is 345 MHz. The voltage applied to the junction to produce this current was

The Electric Field I: Discrete Charge Distributions

The Electric Field II: Continuous Charge Distributions

Electric Potential

Capacitance

Electric Current and Direct-Current Circuits

The Magnetic Field

Sources of the Magnetic Field

Magnetic Induction

Alternating-Current Circuits

Maxwells Equations and Electromagnetic Waves

Properties of Light

Optical Images

Interference and Diffraction

Wave Particle Duality and Quantum Physics

Applications of the Schrodinger Equation

Atoms

Molecules

Relativity

Nuclear Physics

Elementary Particles and the Beginning of the Universe

Filters

The resistivity of copper at 20ºC is 1.7* 10^-8 $\Omega$ · m. You have copper wire whose diameter is 2.00 mm and need a resistance of 1.00 $\Omega$ . How long would a piece of this wire need to be to provide this resistance?

Using the measured mass density of 2.48 g/cm³, and the molar mass of 58.098 g for KF, the equilibrium spacing between the K⁺ and F^- ions is

Which of the following expressions correctly describes the dependence of the resistivity $\rho$ on the electronic mass, m_e, the number of conduction electrons n_e, the electronic charge e, the mean electron speed v_av, and the mean free path $\lambda$ ?

Use the following to answer the next question. -The speed of a conduction electron whose energy is equal to the Fermi energy E_F for magnesium is